P1181: REAL-LIFE TREATMENT APPROACHES AND THERAPY RESULTS IN THE PATIENTS WITH PRIMARY MEDIASTINAL B-CELL LYMPHOMA: POLISH-UKRAINIAN EXPERIENCE
Authors: Kateryna Filonenko, Agata Szymańska, Yana Stepanishyna, Nazar Shokun, Tetiana Skrypets, Massimo Federico, Irina Kryachok, Martina Manni, Jan Zaucha
Journal: HemaSphere (2023)

Topic: 19. Aggressive Non-Hodgkin lymphoma - Clinical Background: Primary Mediastinal B-cell Lymphoma (PMBCL) is a rare subtype of aggressive B-cell lymphomas, which characterizes a favorable outcome after the 1st-line treatment with an appropriate chemotherapy regimen. In contrast, relapsed/refractory (RR) PBMCL has a poor prognosis, and the “best treatment approach” is not determined Aims: To evaluate real-life treatment approaches in patients with PMBCL Methods: We performed a retrospective analysis of the data of the adult patients with PMBCL, diagnosed in 2015-2022 in the University Clinical Center in Gdansk, Poland and National Cancer Institute in Kyiv, Ukraine. Patients were diagnosed and treated according to the local standards of care. We have analyzed demographic characteristics, treatment approaches, including the use of radiation therapy (RT), and treatment outcomes. Results: The Polish patients’ population includes 22 patients with a median age 35 [27-70] yo., 8 males, 14 females. In the 1st-line patients were treated with R-DA-EPOCH regimen in 19 cases (86.4%) and R-CHOP in 3 cases (13.6%). RT was used in 3 patients as a part of the initial treatment only (13.6%). The overall response rate (ORR) was 80%. RR forms were observed in 3 patients. The treatment approaches in the cases of RR PBMCL were as follows: brentuximab vedotin (Bv) plus nivolumab and R-MIV. Autologous stem cell transplantation (auto-SCT) was used in the 2 patients. Third-line and further-line treatment were used in 1 patient (clinical trial) with allogenic stem cell transplantation (allo-SCT) as a consolidation (due to secondary AML). The Ukrainian patients’ population includes 63 patients with a median age 36 [19-78] yo., 26 males, 37 females. The 1st-line treatment regimens were R-DA-EPOCH (52 patients, 82.5%) and R-CHOP-like regimens (11 patients, 17.5%). RT was used in 8 patients (12.7%) as a part of initial treatment only. Among patients with known response, the CR rates for R-DA-EPOCH and R-CHOP regimens were 37 (80.4%) cases vs 0, PR - 5(10.9%) vs 4(71.4%), PD - 4(8.7%) vs 2 (28.6%) respectively. The ORR was 88.7%. RR forms were observed in 7 patients. In the 6 cases, the R-ICE and 1 case R-DHAP were chosen as 2nd-line regimen, all patients had PD. One patient underwent palliative regimen PEP-C, 5 patients received R-GVP treatment, one had PR and proceeded to autologous SCT. Further-line treatment (maximum of 5 lines) were pembrolizumab in 3 cases, RB, nivolumab and CAR-T cells, each single case. The 5-year progression-free survival (PFS) were 84.4% in the Polish patients’ population and 90.1% in the Ukrainian patients’ population (p=0.598). The 3-year overall survival (OS) was 100 and 88.5%, respectively (p=0.431). The 5-year overall survival (OS) was 90.0 and 88.5%, respectively (p=0.431). The only one death observed in the Polish population was due to the complications of the allo-SCT as a secondary AML treatment. The 7 patients died in Ukrainian population (2 cases due to infections, 2 – PD, 3 – unknown). Summary/Conclusion: The 85 patients from Polish and Ukrainian populations were comparable in terms of demographic characteristics, approaches to the 1st-line treatment and ORR. The 2nd and further-line treatment approaches were the major difference between two populations. The treatment with nivolumab +/- Bv was very effective in obtaining CR in all cases. Unlikely, the Ukrainian approach to the salvage treatment was based on classic chemotherapy regimens and resulted in further PD in 6 cases out of 7. The distinction between treatment approaches could be explained by the socio-economic circumstances and restricted access to novel drugs. Despite the absence of significant differences in the OS, we do believe that novel drugs are the best treatment of the RR forms of PMBCL instead of classical chemotherapy.Keywords: Lymphoma therapy, Salvage chemotherapy, Non-Hodgkin’s lymphoma, Immune therapy